Exploring Li-CO₂ batteries with electrospun PAN-derived carbon nanofibers and Li_1.4Al_0.4Ti_1.6(PO₄)₃ solid-state electrolyte

This study introduces a highly stable and conductive sodium super ionic conductor-type solid electrolyte, Li_1.4Al_0.4Ti_1.6(PO₄)₃ (LATP), to address safety concerns and mesoporous-structured polyacrylonitrile (PAN)-derived carbon nanofibers (CNFs) as a cathode material, which has the advantages of high affinity and adsorption of CO₂ gas. LATP, an inorganic solid electrolyte, was synthesized using a solution-based method and its structural properties were assessed using X-ray diffraction and Raman spectroscopy. The ionic conductivity of LATP pellets was approximately 5.87 × 10⁻⁴ S cm⁻¹. The gas adsorption properties and pore size distributions of the electrospun PAN-derived CNFs were analyzed using the Brunauer-Emmett-Teller method. A fabricated Li-CO₂ battery successfully operated for 50 cycles with a current density of 50 mA g⁻¹ and a cut-off capacity of 500 mAh g⁻¹. Finally, a post-mortem analysis of the Li-CO₂ battery was conducted using field-emission scanning electron microscopy and Raman and X-ray photoelectron spectroscopy to examine the electrode degradation mechanism. The analysis indicated that Li₂CO₃ was produced by the electrochemical reaction in the Li-CO₂ batteries, causing electrode degradation. Therefore, improving the sluggish kinetics of Li₂CO₃ decomposition using a catalyst embedded in PAN-derived CNFs will realize high-performance Li-CO₂ batteries.